1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Driver for the ps-mode pin configuration. 4 * 5 * Copyright (c) 2021 Xilinx, Inc. 6 */ 7 8 #include <linux/delay.h> 9 #include <linux/err.h> 10 #include <linux/gpio/driver.h> 11 #include <linux/io.h> 12 #include <linux/kernel.h> 13 #include <linux/module.h> 14 #include <linux/platform_device.h> 15 #include <linux/slab.h> 16 #include <linux/firmware/xlnx-zynqmp.h> 17 18 /* 4-bit boot mode pins */ 19 #define MODE_PINS 4 20 21 /** 22 * modepin_gpio_get_value - Get the state of the specified pin of GPIO device 23 * @chip: gpio_chip instance to be worked on 24 * @pin: gpio pin number within the device 25 * 26 * This function reads the state of the specified pin of the GPIO device. 27 * 28 * Return: 0 if the pin is low, 1 if pin is high, -EINVAL wrong pin configured 29 * or error value. 30 */ 31 static int modepin_gpio_get_value(struct gpio_chip *chip, unsigned int pin) 32 { 33 u32 regval = 0; 34 int ret; 35 36 ret = zynqmp_pm_bootmode_read(®val); 37 if (ret) 38 return ret; 39 40 /* When [0:3] corresponding bit is set, then read output bit [8:11], 41 * if the bit is clear then read input bit [4:7] for status or value. 42 */ 43 if (regval & BIT(pin)) 44 return !!(regval & BIT(pin + 8)); 45 else 46 return !!(regval & BIT(pin + 4)); 47 } 48 49 /** 50 * modepin_gpio_set_value - Modify the state of the pin with specified value 51 * @chip: gpio_chip instance to be worked on 52 * @pin: gpio pin number within the device 53 * @state: value used to modify the state of the specified pin 54 * 55 * This function reads the state of the specified pin of the GPIO device, mask 56 * with the capture state of GPIO pin, and update pin of GPIO device. 57 * 58 * Return: None. 59 */ 60 static void modepin_gpio_set_value(struct gpio_chip *chip, unsigned int pin, 61 int state) 62 { 63 u32 bootpin_val = 0; 64 int ret; 65 66 zynqmp_pm_bootmode_read(&bootpin_val); 67 68 /* Configure pin as an output by set bit [0:3] */ 69 bootpin_val |= BIT(pin); 70 71 if (state) 72 bootpin_val |= BIT(pin + 8); 73 else 74 bootpin_val &= ~BIT(pin + 8); 75 76 /* Configure bootpin value */ 77 ret = zynqmp_pm_bootmode_write(bootpin_val); 78 if (ret) 79 pr_err("modepin: set value error %d for pin %d\n", ret, pin); 80 } 81 82 /** 83 * modepin_gpio_dir_in - Set the direction of the specified GPIO pin as input 84 * @chip: gpio_chip instance to be worked on 85 * @pin: gpio pin number within the device 86 * 87 * Return: 0 always 88 */ 89 static int modepin_gpio_dir_in(struct gpio_chip *chip, unsigned int pin) 90 { 91 return 0; 92 } 93 94 /** 95 * modepin_gpio_dir_out - Set the direction of the specified GPIO pin as output 96 * @chip: gpio_chip instance to be worked on 97 * @pin: gpio pin number within the device 98 * @state: value to be written to specified pin 99 * 100 * Return: 0 always 101 */ 102 static int modepin_gpio_dir_out(struct gpio_chip *chip, unsigned int pin, 103 int state) 104 { 105 return 0; 106 } 107 108 /** 109 * modepin_gpio_probe - Initialization method for modepin_gpio 110 * @pdev: platform device instance 111 * 112 * Return: 0 on success, negative error otherwise. 113 */ 114 static int modepin_gpio_probe(struct platform_device *pdev) 115 { 116 struct gpio_chip *chip; 117 int status; 118 119 chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL); 120 if (!chip) 121 return -ENOMEM; 122 123 platform_set_drvdata(pdev, chip); 124 125 /* configure the gpio chip */ 126 chip->base = -1; 127 chip->ngpio = MODE_PINS; 128 chip->owner = THIS_MODULE; 129 chip->parent = &pdev->dev; 130 chip->get = modepin_gpio_get_value; 131 chip->set = modepin_gpio_set_value; 132 chip->direction_input = modepin_gpio_dir_in; 133 chip->direction_output = modepin_gpio_dir_out; 134 chip->label = dev_name(&pdev->dev); 135 136 /* modepin gpio registration */ 137 status = devm_gpiochip_add_data(&pdev->dev, chip, chip); 138 if (status) 139 return dev_err_probe(&pdev->dev, status, 140 "Failed to add GPIO chip\n"); 141 142 return status; 143 } 144 145 static const struct of_device_id modepin_platform_id[] = { 146 { .compatible = "xlnx,zynqmp-gpio-modepin", }, 147 { } 148 }; 149 150 static struct platform_driver modepin_platform_driver = { 151 .driver = { 152 .name = "modepin-gpio", 153 .of_match_table = modepin_platform_id, 154 }, 155 .probe = modepin_gpio_probe, 156 }; 157 158 module_platform_driver(modepin_platform_driver); 159 160 MODULE_AUTHOR("Piyush Mehta <piyush.mehta@xilinx.com>"); 161 MODULE_DESCRIPTION("ZynqMP Boot PS_MODE Configuration"); 162 MODULE_LICENSE("GPL v2"); 163